Oil cooler question

[preludeman92]

I think I'm gonna want an oil cooler on my motor when I get it done, but I don't really want to mess with a thermostat and a seperate air/oil cooler. The radiator I have is for an auto, so it has the trans fluid cooler built into it. What do you guys think about using that as my cooler? It should function like the stock h22/h23 cooler, right? Those just ran the engine coolant past the oil to help keep the temps in check (both warm and cool). The radiator should work the same, correct? I could always change it to external or add an external cooler if this one doesn't keep it cool enough.
Thoughts?

[The G-Man]

The auto radiator does not send auto trans fluid through the radiator, just coolant to the passages in the tranny.

So, if you tried to utilize this for an oil cooler you would still need something to put the oil and coolant next to each other.

[preludeman92]

Are you sure? From what I've seen on a couple radiators there is a vessel in the bottom tank of the radiator that trans fluid runs though with coolant on the outside of it.

[The G-Man]

I am pretty damn sure it is just coolant. I remember when I helped 90cb7sleeper with his 5 spd swap we took that line off and coolant came out.

[sulimed]

sure his stuff wasn't F-up. when i repaced my radiator on my auto i had tranny fluid every where when i pulled the lines off.

whether or not you can use the.....IDK. but the tranny fluid dose run thru it.

[HondaFan81]

The ATF lines in an auto radiator or universal replacement radiator are separate from the coolant passages within the radiator. They do not mix, if this is what any of you are implying.

upper/lower radiator hose ports on radiator = coolant

two smaller ports at bottom of radiator = ATF

Anyways, similar concept to stock oil cooler it seems, but I haven't taken a look at the mechanics of it to determine differences. What I wonder on oil cooler system is, depending on how well it works, cooling down the oil has to be done within a certain temp range doesn't it? You would not want your oil to get too cool when you're putting your motor under high stress. So it seems like you have to go with a system, then monitor your oil temp gauge to see if the oil temps are good under all conditions and not cooling down the oil too much, but just remaining stable under conditions that normally would cause the oil temps to get hotter...right? Then you have the variable of different ambient temps, etc affecting this system.

I wonder if anyone has stock oil system vs oil temps data....then taking that and comparing it to "oil cooler installed vs oil temps" data to see how much of an affect it would have. I wonder if some kind of temperature controller is needed within this oil cooling system to let the oil get cooled or not, based on the core engine oil system temp to keep it in a good range for proper lubrication.

[HondaFan81]

Anyhow, on my white project I am going to run it as-is and keep an eye on the oil temps, if I need to bring down the temps, I will base it off this information rather than just installing it based on no data. The type of oil you use makes a big difference here as well, just too many variables, the engine bearing clearances I used, etc.

[preludeman92]

It appears the VW TDI guys prefer to upgrade to a larger OEM sandwich cooler like what is on our h22/h23 motors. They have several to choose from. They also tend to stick an auto trans radiator in their 5speed cars when they go out for a canyon run or out on the track regularly. Either or both of these mods keep their oil at 185-205*F depending on what temp their coolant thermostat is. The oil stays at a very constant temp and warms up quickly. One guy says he does open track days with his car and his oil temps never go above 195 which is where his thermostat is set to open. I can live wih that.

From what I've read 200*F is about perfect oil temp and 240-250 is where oil starts to break down. I've also seen you don't want the oil temp do go below 170*F.

I was talking to one of my buddies that has a turbo 89 prelude and she says her oil temps get to 230 when she's messing around on the highway and have seen 250 at the drag strip. Her BF has an NSX. It sees 205*F crusing around and 215 when you beat on it because it's got a small sandwhich cooler.

Cisco, do you have oil temps on either car yet?

[NAiL05]

I think as mentioned a bigger sandwich cooler should suffice but it depends on how hardcore you are going on the build. The Ideal temp range for oil is usually around 180-200. In that range. Oil coolers for some engines CAN overcool the oil making the oil sludge and whatnot. So it is best to find a proper sizing to prevent that from happening. As for the trans itself its a different story since there is no cooling apparatus only the two lines that come out to the small cooler. The oil has coolant and such around it to help it keep a certain temp. But yea depends on your setup.

[preludeman92]

This motor will create more than enough heat at 12:1 compression and 7000rpm, so I think cooling will become necessary.
I don't have a sandwhich cooler on my motor now. This would be like adding one, just in a different place on the motor. I can't decide if I want to do this immediately or not though. It'd add $150+ to my already growing cost that is far beyond what I had planned to spend.
I have a feeling that this will come later after I see the oil temps after my first track day in June.

[HondaFan81]

It appears the VW TDI guys prefer to upgrade to a larger OEM sandwich cooler like what is on our h22/h23 motors. They have several to choose from. They also tend to stick an auto trans radiator in their 5speed cars when they go out for a canyon run or out on the track regularly. Either or both of these mods keep their oil at 185-205*F depending on what temp their coolant thermostat is. The oil stays at a very constant temp and warms up quickly. One guy says he does open track days with his car and his oil temps never go above 195 which is where his thermostat is set to open. I can live wih that.

From what I've read 200*F is about perfect oil temp and 240-250 is where oil starts to break down. I've also seen you don't want the oil temp do go below 170*F.

I was talking to one of my buddies that has a turbo 89 prelude and she says her oil temps get to 230 when she's messing around on the highway and have seen 250 at the drag strip. Her BF has an NSX. It sees 205*F crusing around and 215 when you beat on it because it's got a small sandwhich cooler.

Cisco, do you have oil temps on either car yet?

No monitoring gauges on the red. No driving oil temps on the white, just parked/idle revving it was between 125 F and 150 F.

[HondaFan81]

This motor will create more than enough heat at 12:1 compression and 7000rpm, so I think cooling will become necessary.
I don't have a sandwhich cooler on my motor now. This would be like adding one, just in a different place on the motor. I can't decide if I want to do this immediately or not though. It'd add $150+ to my already growing cost that is far beyond what I had planned to spend.
I have a feeling that this will come later after I see the oil temps after my first track day in June.

Amazing isn't it how the list grows and the expense too? I too am going this route and first observing what my oil temps are on the street. Road racing is a complete different animal when you keep the motor rung out constantly, things happen and you need to compensate. I just want to see how it acts on the street first to gauge what I need to improve to keep the motor stable later. I will not introduce the white project to abuse until I know it's capable and that goes for long trips, it has to gain my confidence first.

[preludeman92]

Where I typically road race only has 20 minute sessions and the course isn't terribly fast. We were topping out about 100mph in non-vtec cars and 110-115 in VTEC cars. I can always sit out a round or two if heat becomes a problem.

My list grew because I was on a tight budget, then Christmas came and my budget got a lot bigger because my grandparents gave me a really nice check and said spend it, but don't waste it. They called it fun money.

What started out as trying to keep under $1000 before tuning just went to about 3x the cost plus more tuning than I was planning on before.

[HondaFan81]

Where I typically road race only has 20 minute sessions and the course isn't terribly fast. We were topping out about 100mph in non-vtec cars and 110-115 in VTEC cars. I can always sit out a round or two if heat becomes a problem.

My list grew because I was on a tight budget, then Christmas came and my budget got a lot bigger because my grandparents gave me a really nice check and said spend it, but don't waste it. They called it fun money.

What started out as trying to keep under $1000 before tuning just went to about 3x the cost plus more tuning than I was planning on before.

Keep me posted on your road racing experience and oiling system modification status. I'm interested and some day can perhaps join you and your Prelude crew, when mine is ready for it.

[NAiL05]

How about trying out a sandwich plate first and see how much heat it might dissipate? It might be cheaper than going all out with a 150 dollar cooler right off the bat. Dunno just sayin. Pretty abundant around junkyards.